Description

Due to the double spider vanes of carbon fibre which have 11 mm distance to each other, the stiffness after mounting matches the one of a metal secondary mirror spider with vanes of 5 mm diameter.

The carbon vanes have a thickness of only 0.4 mm. This means minimal obstruction and extremely fine, subtle spikes around the brighter stars. The diffraction effects caused by the spider remain minimal.

Do twin spider vanes cause twin diffraction spikes at the stars?

Of course not! Once you have attained precise focus both spikes will merge into one very fine spike.

Double spider vanes as focusing aid:

Twin spider vanes are more sensitive to slight blurring due to inaccurate focusing than a single spider vane. This makes focusing on brighter stars easier. As soon as the spikes are clearly merged to one, focus has been exactly reached. Of course, all popular focusing aids, like a bahtinov mask, also work with the double spider.

Sidereal Trading offers a discount off non-sale items to selected Astronomy Clubs and Societies. If you are a member of the ASV, MBO, MPAS, SV or ASSA email sales@siderealtrading.com.au to receive your DISCOUNT COUPON. Dismiss